Powder compaction and enrobing

ABSTRACT

Powder, e.g. of a medicament, is compacted and enrobed to produce compacted powder slugs by preferably mechanically compacting a powder and forming a film of material, preferably hydroxy propyl methyl cellulose, by vacuum or pressure differential, about the surface of the powder thus compacted.

FIELD OF THE INVENTION

This invention concerns the compacting of powder e.g. a powdercontaining a medicament, vitamin, dietary supplement etc, and suchcompacted powder being enrobed by a biodegradable and/or water solublefilm, for example a non gelatin film, such as hydroxypropyl methylcellulose (HPMC), to produce encapsulated bodies of compacted powder,suitable for dosage forms, e.g. for human ingestion. The invention isapplicable to all related dosage forms, including tablets, but forsimplicity all such forms will be generally referred herein as capsules.

BACKGROUND TO THE INVENTION

Tablets are a common type of dosage form and various means for improvingtheir properties have been tried. Current methods for coating tablets,such as pharmaceutical tablets include the using of acelacoaters or pancoaters, which spray low molecular weight HPMC grades onto tablets soimparting a surface layer, which is uniform and smooth, but opaque andof low gloss. It is possible for the tablets to have embossed letteringon them. This method of coating tablets is however very time consumingand requires a high level of expertise to produce satisfactory results.Production complications such as tablet twinning are common, where twotablets become attached to one another during the spray coatingoperation. In addition to these problems it is necessary to compact thetablets under relatively high pressures so that they do not disintegrateduring the coating process. This high level of compaction can have anadverse effect on the disintegration and dissolution rates of activeingredients contained within the capsule, for example, leading to adelay in the release of a drug to a patient, whilst the tablet slowlydissolves in the stomach of the patient.

An alternative to spray or pan coating is to use two-piece hardcapsules. These are produced by a dipping process, typically a HPMCsolution is used, producing half shells which interlock and thus producean enclosed capsule. These capsules are typically opaque but glossy, andcannot have any form of embossment, as this would interfere with theoverlap interlocking process. The nature of the capsule dictates thatthere will always be an airspace above the powder fill level.Additionally, it is not possible to compact the powder into thesetablets, and this so limits the quantity of powder which can beencapsulated. It follows that this lack of compaction can effectivelyreduce the amount of e.g. medicament which can be encapsulated. Theexistence of the air space in the capsule and lack of compaction of thepowder contained within the capsule leads to a capsule that isinevitably larger than necessary.

It has also been found that, after manufacture and/or sale of two-piecehard capsules, the capsules can be easily and illegally interfered with,as it is possible to separate the two halves of the capsule and tamperwith its contents and replace the two halves back together without therebeing any obvious change in the capsule's external appearance such tosuggest to the user that there was anything wrong with the capsule. Thismeans that it can be difficult to detect capsules which have had theircontents tampered with.

HPMC and certain other non-gelatin materials are suitable for ingestionby humans, so delivery capsules with gelatin walls find potential use asingestible capsules, e.g. for the delivery of accurately metered dosesof pharmaceutical preparations and dietary supplements, as a possiblereplacement for gelatin based capsules. Conventional tablets havealready been enrobed. See for example WO 02/098394.

SUMMARY OF THE INVENTION

One aspect of the invention concerns a novel method for compacting andenrobing a powder to produce capsules with enhanced properties.

A non gelatin film layer is thermoformed into a suitable tablet shapedpocket under the influence of heat and/or vacuum, and/or pressure. Apre-determined mass of powder is dosed into the film formed pocket, andcompressed into a tablet shape e.g. with the aid of a piston or pistons.A partially enrobed ‘soft’ tablet results from this process, which isthen fully enrobed by a second sequence of events which involves theraising of the tablet above a platten which allows the remainder of thecompressed tablet to be enrobed by a second film. Suitable tablet shapedpockets can be created by using e.g. a pair of pistons slideable withina cylinder, such pistons also having the advantage of being able to formpinch points between the platen and the top of cylinders which areuseful for cutting away unwanted excess film from the (partially)enrobed tablets.

One of the aims of the present invention is to produce tamper evidentcapsules.

Another aim of the present invention is to produce powder filledcapsules whereby the powder is enrobed with a material which may or maynot form a ‘skin tight wrap’.

Another aim of the present invention is to produce a capsule with a highgloss surface which is able to adopt an underlying embossment, e.g. toidentify a pharmaceutical tablet.

Another aim of the present invention is to produce capsules which have aflange which is almost non-discernable.

Another aim of the present invention is to enable the production ofdosage forms in a wide variety of shapes and sizes, which, because ofthe nature of the processes involved and the properties of the productproduced, includes shapes and sizes of dosage forms which have not beenpreviously possible to make or practical to use.

Another aim of the present invention is to produce capsules withfavourable properties and which contain powder or other flowable solidmaterial which is at a favourable state of compaction and/orcomposition, and/or the encapsulating medium of the capsule being fastdissolving or dissolvable (with control) pharmaceutical grade filmsplasticised with pharmaceutical grade materials.

Another aim of the present invention is to produce capsules, which bytheir nature, are easy to swallow, and more easily can be conveyed tothe site where it is desirable where the active ingredients are mostadvantageously released.

Another aspect the present invention is a method of powder compaction toproduce powder compacted slugs, which, for example can be enrobed toproduce capsules which possess enhanced disintegration and dissolutionproperties over and above traditional tablets.

Another aspect of the present invention is a method of producing acapsule, which, at the very least can perform the same function as aconventional coated tablet, but in which the conventional tabletpressing and coating stages are replaced by a single powder enrobingprocess.

Another aspect of the present invention is a method of producing acapsule by enrobing powder, in which, because of the nature of capsuleproduced, certain ancillary ingredients necessary in conventional tabletproduction, can be omitted. For example, ingredients in a tablet whichare added to give the tablet its structural integrity can be omitted,because the active ingredients are in powder form, relatively looselycompacted are encapsulated within a film, such film which now securelypackages the powder/ingredients, thus giving integrity and forming adiscrete effective dosage form. Because of the aforementioned,components contained within a tablet which are designed to disperse andbreak up the tablet when it has reached the site of delivery, can beomitted, as the active ingredients in the capsule according to thepresent invention are in a non-compacted or at least less compacted formas compared to a conventional tablet, and this lesser compaction leadsto the easy release and dispersal of active ingredients once the capsulefilm has dissolved, e.g. at the intended site of delivery.

Another aspect of the invention provides a method of enrobing compactedpowder, comprising vacuum forming a film into a pocket, compacting apowder in said pocket, resulting in a partially enrobed powder slug in apocket. Vacuum forming a second film over this powder slug to completelyenrobe the powder slug, forms a discrete compacted powder filledcapsule, suitable for use as a dosage form.

In yet another aspect of the present invention provides a method ofenrobing compacted powder using film or films, to form a compactedpowder filled capsule, wherein the film or films forming the wall of thecompacted powder filled capsule used overlap each other.

In a further aspect of the present invention provides a method offorming and/or enrobing a compacted slug wherein the level of compactionof the compacted powder is less than that necessary to reach theindustry standard for the discrete slug of compacted powder to bedescribed as a tablet.

In practising the method of the invention, the films are caused todeform to conform with the external surface of the pocket and thecompacted powder slug, the films effectively forming a secure capsule,by being wrapped around the powder slug. Vacuum chamber or vacuum bedapparatus, in which the films and powder are located in a suitablyshaped support and exposed to conditions of vacuum (or substantiallyreduced pressure) can be modified and used for this purpose. Suchapparatus may be based on commercially available vacuum chamber orvacuum bed apparatus, suitably modified. Vacuum forming techniquesresult in the compacted powder being completely enclosed andencapsulated within a film, leading to a capsule containing compactedpowder, such capsule having enhanced and controllable properties overdosage forms currently available, such as conventional tablets. Thepowders to be compacted are typically subjected to pressures between,but not limited to, 5-15 mega pascals. Examples of powders compacted andenrobed include paracetamol, ibuprofen, sorbitol and multivitamin. Otherpowder fills which are contemplated are antacid, anti-inflammatory,anti-histamine antibiotic and anti-cholesterol drugs.

The film should be a material which is suitable for human consumptionand that has sufficient flexibility and plasticity to be vacuumformable. Some film materials have suitable properties in their naturalcondition, but commonly it will be necessary to pre-treat the filmmaterial so that it is vacuum formable. For example, it may be necessaryto expose the film material to a solvent therefor; for instance certaingrades of polyvinyl alcohol (PVA) will vacuum form after application ofa small amount of water to the surface thereof or when exposed toconditions of high humidity. A further generally preferred possibility,is to use a film of thermoplastic material (i.e. material capable ofdeforming plastically on heating) with the film to be in heat-softenedcondition prior to being thermoformed by exposure to vacuum. Suitablethermoplastic materials include modified cellulose materials,particularly hydroxypropyl methyl cellulose (HPMC) and hydroxypropylcellulose (HPC), polyvinyl alcohol (PVA), polyethylene oxide (PEO),pectin, alginate, starches, and modified starches, and also proteinfilms such as soya and whey protein films. The currently preferred filmmaterial is HPMC. Suitable film materials are currently available.

When using thermoplastic film, the film is typically heated prior toapplication to pocket or compacted powder slug, so that the film is in aheat softened deformable condition. This can be achieved by exposing thefilm to a source of heat e.g. an infrared heater, infrared lamps, aheated plate a hot air source etc. In the process described, a range oftemperatures may be used, but by way of example only, where films ofdifferent thickness may be utilized for the first and second films inthe process, a first film forming temperature of around 150 degreescentigrade may be used and for the second film forming stage, a range ofapproximately 70-80 degrees centigrade may be used.

During the enrobing process, films may be caused to overlap, preferablya minimum of 1.5 mm-2 mm. Compacted powder slugs may preferably have asidewall height of about 3 mm and films may be caused to overlapsubstantially completely over the sidewall area.

The film material may include optional colourings, e.g. in the form offood dyes such as FD and C yellow number 5, and/or optional flavourings,e.g. sweeteners, and/or optional textures etc in known manner.

The film material typically includes plasticiser to give desiredproperties of flexibility to the film in known manner. Materials used asplasticisers include alpha hydroxy acids such as lactic acid and saltsthereof, maleic acid, benzyl alcohol, certain lactones, diacetin,triacetin, propylene glycol, glycerin or mixtures thereof. A typicalthermoplastic film formulation is HPMC 77% by weight, plasticiser 23% byweight.

The film suitably has a thickness in the range 20-200 microns,conveniently 50 to 100 microns, e.g. at about 80 microns, withappropriate film thickness depending on factors including the size andform of the tablet. Films of different thickness may be used, e.g. afilm of greater thickness may be used in the first stage of the enrobingprocess, say 125 microns thickness and a film of lesser thickness may beused in the second stage of the enrobing process, say 80 micronsthickness.

Because of the nature of the film forming process according to thepresent invention, under certain circumstances, e.g. where the powder tobe compacted contains particles which, under compaction, have theability to pierce film, it may be advantageous to have the thickness ofthe film formed in the pocket to be greater than that of the film whichis to cover the remainder of the compacted powder slug (in the secondand final phase of enrobement of the compacted powder). Suchdifferential thickness may give rise to certain advantageous structuralfeatures of the resultant capsule; the capsule my be generally morerobust and so may be more safely stored and handled (generally thickerfilm on the capsule), but such capsule also possessing a smaller area(window) of weaker, thinner film which can give rise to quicker releasecharacteristics by the thinner film will dissolving more quickly whenexposed to any given solvent. An advantageous differential filmthickness to form a capsule with wall of different thickness, could bee.g. 70/90 micron film coordination to produce capsules which are robustbut which release their contents quickly, through a window of thinnerfilm.

Therefore films of different thickness may be used in the enrobingprocess, and to give a further examples, a film of greater thickness maybe used in the first stage of the enrobing process, a maximum of 200microns and a minimum of 70 microns but say preferably 125 micronsthickness and a film of lesser thickness may be used in the second stageof the enrobing process, a maximum of 125 microns and a minimum of 50microns, but say preferably 80 microns thickness. When making multiplesof enrobed compacted powder slugs; the spacing of the compacted powderslugs can be important. If the compacted powder slugs are positioned tooclosely together, the film is not able to fully thermoform between them.For example, a spacing between the adjacent compacted powder slugs ofabout 4 mm has been found to give good results, the film being able tofully adopt the vertical sidewall of the compacted powder slug to adistance of about 2 mm before it begins to curve away from the side ofthe compacted powder slug.

According to one aspect of the invention, the method involves formingtwo separate overlapping half coatings of film, effectively on thecompacted powder slug. The method preferably involves, first forming afilm in a pocket, then compacting a powder slug into the film linedpocket, thereby effectively coating/encapsulating a substantial portionof a powder slug within a film formed into a partial capsule, removingthe remaining film material not coating the compacted powder slug e.g.by cutting, then coating the remaining half of the compacted powderslug, with overlapping portions of the two coatings sealed together toprovide a sealed complete enclosure for the slug, and again removingremaining surplus film material not coated on the slug. It may benecessary to apply adhesive material between the overlapping filmcoatings e.g. to the surface of the film layers, to ensure the formationof an effective seal therebetween and to make the resultant capsuletamper-evident. The adhesive material conveniently has the samecomposition as the film, but with a greater proportion of plasticiser,e.g. 93% to 98% by weight plasticiser, so as to provide a less viscousmaterial. The adhesive material may be applied, e.g. by use of a roller,spraying etc. A typical adhesive formulation, with % representing % byweight, is HPMC 4%, lactic acid 77%, water 19%.

The compacted powder slug and capsule conveniently include a generallycylindrical side wall portion, with two half coatings overlapping onthis side wall. Tablets of circular symmetrical form with a circularcylindrical side wall are very common, but other forms e.g. generallyoblong and oval, again including a generally cylindrical side wall, arealso known.

It may be also advantageous or desirable to apply adhesive material e.g.as described above, to the surface of compacted powder slug prior to thefinal stage of coating, to promote adhesion of the second portion of thefilm thereto. Again, this may be achieved by e.g. use of a roller,spraying etc.

A plurality of tablets in an array may be conveniently coatedsimultaneously, using a suitably large sheet of film material.

This invention is now further described in detail, by way of exampleonly, with reference to the drawings. Steps a-k show the basiccompaction and enrobing apparatus and process.

The drawings show the various stages of a powder compaction/enrobingprocess.

FIG. 1 shows the mechanism of the basic steps of powder compaction andenrobement via steps a-l:

-   -   a. A first film (1) is laid upon a platten (2). Lower piston        (3), slideable in cylinder (4) incorporates vacuum port (5).    -   b. Film (1) completely drawn down into cylinder (4) by a vacuum        created by vacuum port (5) and said film (1) also resting on the        crown of lower piston (3), to form a pocket shape.    -   c. A quantity of powder (6) is introduced over the pocket of        film and upper piston (9) moves downward towards the lower        piston (3) compressing a quantity of powder (6).    -   d. A compacted powder slug (7) resulting from the completion of        step c.    -   e. Cutting of film by the introduction of cutting tool (10) to        form an isolated semi enrobed slug of compacted powder.    -   f. Lower piston (3) begins to move upwards, thereby also urging        compacted powder slug (7) upwards.    -   g. Lower piston (3) comes to rest, positioning compacted powder        slug (7) proud of platen (2)    -   h. Introduction of a second film (8) over platen (2) and also        loosely stretching over compacted powder slug (7)    -   i. Second vacuum is applied drawing second film (8) around and        closely in association with the upper portion of compacted        powder slug (7), second film (8) thereby wrapping itself around        the upper part of the compacted powder slug (7).    -   j. Cutting tool (12) descending and trimming off excess        unwrapped film from powder slug (7).    -   k. Fully enrobed powder slug, has been ejected from cylinder (4)        by the further upward movement of lower piston (3) and has the        loose ends of the films ironed and sealed by irons (13).    -   l. Shows a fully enrobed tablet with ironed seams.

FIG. 2 depicts a variation of the basic process described by FIG. 1.

-   -   Steps a1 and b1 show a second pre-formed film pocket, formed by        a second vacuum forming pocket (14) being lowered onto the        platten immediately above a partially enrobed powder slug as        shown in step f of FIG. 1. Once the opposing film pocket is in        position lower piston (3) moves upwards thus pushing compacted        partially enrobed powder slug also upwards and into the cavity        of the second pre-formed film pocket, thus capping the partially        enrobed powder slug to form a fully enrobed capsule, enrobed by        two pockets of film. The capsule is then released, trimmed and        ironed as mentioned previously.

FIG. 3 depicts a further variation of the basic process described byFIG. 1.

-   -   Step a2 shows a powder slug as in step f of FIG. 1, and like        FIG. 2 a second pre-formed film pocket is introduced, but this        time it is a shallow pocket, formed by a second shallow vacuum        forming pocket (15), such to only coat the top of the powder        slug and to form a seal at the circumference of the very edge of        the cylindrical portion of the powder slug. Steps a2-d2 show        this revised process. This process gives rise to a capsule with        a different type of seal which gives rise to different        properties in the capsule.

FIG. 4 depicts another variation of the process described by FIG. 1.

-   -   However the basic process is essentially duplicated to form a        capsule which contains two distinct half doses of powder. The        basic process as described in FIG. 1 is carried out up to step        f, in duplicate, which is basically steps a3-c3 in FIG. 4. The        main differences at this point in FIG. 4, are that the two        opposing pockets filled with compacted powder (16,17) are half        size in depth, and the top of the powder slugs are essentially        flat, rather than rounded. Step c3 may include the laying down        of an intermediate film on the surface of the half slug. Steps        d3-f3 show the bringing together of 2 half slugs to form a        single capsule, comprised of 2 parts. Step g3 shows a        compartmentalized capsule. The advantages are at least 2        separate doses of active ingredients can be incorporated into 1        capsule, under perhaps different compaction pressures etc. This        gives rise to further flexibility and options as to the        performance of the new dosage forms.

The process described, and in conjunction with the quantity of powderused, with the careful positioning of the co-acting pistons during thecompaction process, can facilitate the formation of powder slugs havingvarious levels of compaction. As previously described, these varyinglevels of compaction are allowed in the powder slugs because the slugsare enrobed within a film, and it is this film enrobement which providethe slug with the necessary integrity it needs so that it can functionas a convenient and stable dosage form. The process and apparatus can bemodified such to produce capsules with varying properties, which haveadvantages over tablets and conventional capsules already known in theart. For example, a capsule according to the present inventioncontaining a powder with a low compaction, could produce extremelyfavourable quick release characteristics, suitable, e.g. for a fastacting-analgesic; the film can be both designed to be smooth/flexible,to allow the capsule to quickly and relatively painlessly travel to theintended site of drug delivery through the digestive tract, and also bedesigned to dissolve at or near the intended site of drug delivery. Thelower compaction of the powder in the capsule can also aid smooth travelof the capsule in the digestive tract, as the contents of the capsulecan be designed to be compressible and mobile, thus allowing the capsuleto be bent and/or compressed as it travels through the body so that itcan conform to the shape of a more restricted part of a passage, squeezethrough it and so continue its journey through the digestive tract withless hindrance. Such dosage forms may find themselves especially usefulwhere a patient finds difficulty in swallowing, has a painful orrestricted digestive tract, or there is some other reason why a dosageform is required to be more mobile and less aggressive to the internalsof the body.

The following methods are given by way of example and it is not intendedto limit the invention in any way:

EXAMPLE 1

Consumable Items:

Film 1—125 micron thickness, hpmc plasticised with lactic acid 15%, andtriacetin 5%, processing aids starch 1% and sorbitol monostearate 0.25%.

Film 2 as film 1 but 80 micron thickness.

Glue applied to overlap area of first film—benzyl alcohol 45%, triacetin50%, hpmc E15 Premium (Dow Chemical Corp.) 5%

Process Description

Film 1 is thermoformed into single or multiple tablet/caplet shapedpockets in a platen, each pocket containing a lower piston that can beraised or lowered as necessary to suit standard sized tablets andcaplets. The tablet shaped pocket also has a raised edge profile aroundthe top perimeter of the pocket. This edge profile is raised 1 mm abovethe platen surface and has a land width of 0.35 mm. The verticalsidewall of these pockets is typically 3 mm deep.

The thermoforming operation involves the film acting as a membranedividing the two halves of a vacuum chamber, which are separatelycontrolled. The chamber above the film contains a flat heated platen ata temperature of approximately 150° C. Vacuum is drawn above the filmcausing it to be held against the heated plate for a period of 1 to 5seconds preferably 3 seconds. The vacuum in the upper chamber ismaintained whilst vacuum is also applied to the lower chamber. At thisstage the film remains against the heated platen. Once the vacuum levelin the lower chamber reaches at least −0.65 bar the vacuum in the upperchamber is released to atmosphere or replaced by positive pressure, thisforces the film downwards away from the heated platen and onto thetablet pocket shaped tooling below. In this way the film adopts theshape of the tablet pockets in the lower tooling.

Powder Dosing and Film 1 Cutting

A dosing assembly is then placed over the film formed pocket. Thisconsists of a location mask which sits on location dowels in the platen,and a dosing sleeve that rests directly above the film formed pocket,and sits on the raised edge profile. The dosing sleeve exactly matchesthe dimensions of the film formed pocket. A dose of powder is depositedinto the dosing sleeve and falls into the film pocket. Compaction isachieved via a compaction piston that advances through the dosing sleeveand sweeps any residual powder down into the film pocket below andcompacts it to a fixed stop, such that it does not cut the film, butinstead comes to rest directly adjacent to the film. The level ofcompaction is controlled by the mass of powder being deposited into thedosing sleeve. The piston below the compacted powder tablet is thenlowered and either the compaction piston is advanced by a similar amountcausing a punch cut through the film as it interferes with the inside ofthe raised edge profile. Alternatively the compaction piston is replacedby a cut piston which similarly advances and causes a punch cut with theraised edge profile. The fit tolerance between the cut piston and theinternal dimensions of the raised edge profile are such that thediametric clearance is no more than 35 microns.

The apparatus is generally of stainless steel, with the piston crownsmade of hardened steel. The equipment was machined and supplied byMidland Tool and Design, Birmingham, UK.

The tablet is thus pushed down by the cut piston into the confines ofthe pocket, and comes to rest on the lower piston. The location mask anddosing sleeve and the waste film web are then removed.

Second Film Application, Cut and Iron

The partly enrobed core is then raised upwards within the tooling, suchthat half of the formed tablet sidewall is above the raised edgeprofile. The second film has 15 gsm of glue applied to its surface viagravure roller and this is advanced over the tablets. The film is thenthermoformed in the same manner as described for the first film, exceptthat the film is held above the tablets by a spacer plate, such that thepositioning of the film does not damage the top surface of the tablet.It is possible to use a lower heated platen temperature (50-150° C.) forthe second thermoform, as the film is thinner and softened by theapplication of glue. This helps to limit the heat exposure of the powdersurface. The location mask is then positioned over the tablet and asecond cut piston is lowered. The second cut piston is designed suchthat it forms a punch cut on the outside edge of the raised edge profileof the lower tooling, with a diametric fit tolerance of no more than 25microns. The location mask, and second cut piston and waste film web arethen removed and the fully enrobed powder core is pushed through a tightfitting tablet shaped heated cylinder (40° C.) to ensure the overlapseal is formed.

EXAMPLE 2

Same conditions as Example 1, but the following step replaces ‘Powderdosing and film 1 cutting’ stage:

Powder Dosing and Film 1 Cutting

A dosing assembly is then placed over the film formed pocket. Thisconsists of a location mask which sits on location dowels in the platen,and a dosing sleeve that rests directly above the film formed pocket,and sits on the raised edge profile. The dosing sleeve exactly matchesthe dimensions of the film formed pocket. A dose of powder is depositedinto the dosing sleeve and falls into the film pocket. The cut isachieved via the cut piston that advances through the dosing sleeve andsweeps any residual powder down into the film pocket below. The level ofcompaction is controlled by the mass of powder being deposited into thedosing sleeve. The cutting piston cuts through the film as it interfereswith the inside of the raised edge profile. The cut piston continues toengage with the raised edge for a further 1 mm, and in so doing compactsthe powder further into the film shell. The fit tolerance between thecut piston and the internal dimensions of the raised edge profile aresuch that the diametric clearance is no more than 25 microns.

The apparatus is generally of stainless steel, with the piston crownsmade of hardened steel. The equipment was machined and supplied byMidland Tool and Design, Birmingham.

The tablet is thus pushed down by the cut piston into the confines ofthe pocket, and comes to rest on the lower piston. The location mask anddosing sleeve and the waste film web are then removed.

EXAMPLE 3

Same as example 1, but the tolerance fit for the first cut piston is thesame as that for the second cut piston, i.e 25 microns.

EXAMPLE 4

Same as example 2, but the tolerance fit for the first cut piston is thesame as that for the second cut piston, i.e 25 microns.

1. A method of forming a compacted powder slug encapsulated with a film, comprising: forming a film into a pocket using vacuum and/or pressure; compacting a powder into the pocket resulting in a partially enrobed powder slug, wherein at least 15% and a maximum of 99% of the powder slug is enrobed; raising the partially enrobed powder slug above a platten to allow the remainder of the powder slug in said pocket to be enrobed; and enrobing the remainder of the powder slug.
 2. A method according to claim 1, wherein the film comprises thermoplastic material which is heated prior to being vacuum formed.
 3. A method according to claim 1 wherein the means for compacting the powder is mechanical.
 4. A method according to claim 3 wherein said mechanical means for compacting the powder utilizes one or more pistons.
 5. A delivery capsule having an enclosing wall and a powder slug core according to claim
 1. 6. A delivery capsule according to claim 5 whereby the films forming the enclosing walls are overlapping.
 7. A delivery capsule according to claim 5 wherein the delivery capsule has one or more overlapping flanges.
 8. A delivery capsule in accordance with claim 5 wherein the films used or the enclosing wall of the capsule, are made from a non gelatin polymeric material, modified cellulose material, starch material, modified starch material or protein films or graft copolymers of polyethylene oxide with side chains polyethylene oxide.
 9. A delivery capsule in accordance with claim 5 wherein the films used or the enclosing wall of the capsule, are made from hydroxypropyl methyl cellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), polyethylene oxide (PEO), pectin, alginate, soya or whey protein.
 10. An enrobed powder slug according to claim
 1. 11. A method according to claim 1, wherein the films used or the enclosing wall of the capsule are made from a non gelatin polymeric material, modified cellulose material, starch material, modified starch material or protein films or graft copolymers of polyethylene oxide with side chains of polyethylene oxide.
 12. A method according to claim 1, wherein the films used or the enclosing wall of the capsule are made from hydroxypropyl methylcellulose (HPMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), polyethylene oxide (PEO), pectin, alginate, soya or whey protein. 